Synergism of Flame‐Retardant, Self‐Healing, High‐Conductive and Polar to a Multi‐Functional Binder for Lithium–Sulfur Batteries

Abstract

In this work, a multifunctional binder with self‐healing, flame retardant, high conductivity, and abundant polar groups is prepared by the free radical polymerization method and applied to lithium–sulfur (Li‐S) batteries to achieve high safety and exceptional electrochemical performance. The self‐healing characteristic of binder induced by intermolecular hydrogen bonds and SS dynamic covalent bonds can repair volume expansion cracks. The polar groups and excellent conductivity endue binder with strong chemisorption on polysulfides and fast charge transportation, which can effectively inhibit the shuttle effect and accelerate polysulfides redox kinetics. More important, the considerable flame retardant performance of binder can improve the safety of the LiS batteries. As a result, the LiS cells using FHCP binder deliver an outstanding cycle stability of a high‐capacity retention rate of 85% after 100 cycles at 0.2 C, and a high reversible area specific capacity of 5.25 mAh cm–2 at a sulfur loading of 4.72 mg cm–2 and a correspondingly lean electrolyte condition (E/S ratio = 6 µL mg–1).

Review and Perspectives on Advanced Binder Designs Incorporating Multifunctionalities for Lithium–Sulfur Batteries

“…The thermal stable cell delivered impressive cyclability and capacity delivery even at high sulfur loadings. 88 Another cross-linked polymer based on polyethylenimine, polyvinylpyrrolidone, poly(ethylene oxide), and citric acid with superior mechanical properties and abundant functional groups was used as a binder in Li−S batteries. The flexible binder conserved the structural stability of the cathode and controlled the polysulfide shuttle which enabled the cell to deliver longterm cycling stability.…”

“…The functional groups help in polysulfide confinement and accelerate the charge transfer. The thermal stable cell delivered impressive cyclability and capacity delivery even at high sulfur loadings …”

Modulating Bond Interactions and Interface Microenvironments between Polysulfide and Catalysts toward Advanced Metal–Sulfur Batteries

“…In situ Raman spectra is a powerful optical technique to detect the vibrational or rotational modes of functional groups in the molecular structure, which can be used to observe the soluble polysulfide intermediates in the electrolyte during cycling. [68] The Raman spectra of the catholyte region can clearly show the high-order soluble sulfur species involving S The schematic image of the cell used for in situ X-ray radiography. Reproduced with permission.…”

Self-healable, super Li-ion conductive, and flexible quasi-solid electrolyte for long-term safe lithium sulfur batteries

“…48,49 To enhance the Li-ion transport in the cathode layer and the interfacial compatibility between PSE and electrode, the ion conductive binder has been implemented in recent years. [50][51][52][53][54][55] However, these conductive binders had to face mechanical failure by internal stress generated by a huge volume expansion/ shrinkage of S active materials during cycling, which resulted in the rapid deterioration of cycling capacity and performance. 56,57 Because these electro-mechanical decays are difficult to prevent and repair, a new strategy should be considered to alleviate it.…”